Lightroom CC 3.1 just out. Still exporting low res JPGs.

Exporting from a Raw file at either size results in a file thats the same size. Why is this and why is this still happening?
What is the point of allowing a full size JPG to be made, but at a low resolution or high compression? With twice the resolution when using maximum available how can the file size be the same as using the small setting? The desktop version doesn’t do this so why is the mobile version doing it. What possible usage can it be?

An update. It seems if I export the images to the Files app on my iPad/iPhone the sizes vary quite considerably, as you would expect. Exporting a small and maximum version can have a huge difference in file size, but exporting the same image by saving to camera roll gives two images with different dimensions, but the same file size.
Surely this isnt by design?

These are raw files.From a Canon 5D4 raw file. Exporting to the camera roll produces a file that’s 5.6MB, no matter if I use small or maximum size. Exporting the same to the fIles app or anything other than Camera roll gives me a small size of 806KB, and 5.6MB for maximum. Dimensions change as expected for all files.

Yes, 5.6Mb is about right. Having looked in to this a bit more i think its more an IOS11 issue. I might have jumped the gun blaming LR. If i move any of these JPG's out of the Camera Roll, say to iCloud or Dropbox etc, then i get the real file size reported, and its the 2048 size that seems to be the issue. Moving the 2048 pixel file, thats showing as 5.6Mb in Camera Roll, reveals that it is 803KB